Conventionally, magnetic disk devices have been widely used as external storage devices that can transfer large-capacity data at high speed. Particularly, in recent years, disk array devices that include a plurality of mounting devices for disk drive have been used as external storage devices that realize high reliability and low prices (Japanese Laid-open Patent Publication No. 2006-235964, and Japanese Laid-open Patent Publication No. 2003-036669).
A mounting device for disk drive is a device that houses therein a plurality of small-sized magnetic disk drives (hereinafter, referred to as “HDDs”), and that stores data in a distributed manner in each of the HDDs. For such a mounting device, two types of HDDs of a 3.5-inch type (first standard) HDD for low-cost and large-capacity applications, and a 2.5-inch type (second standard) HDD for downsized and high-speed applications are used.
However, such a conventional mounting device described above has a problem in that the two types (3.5-inch type and 2.5-inch type) of HDDs may not be selected optionally to be used according to purposes of a user because the width or the like of the device is specified by the standards (the first standard and the second standard).
More specifically, for such a conventional mounting device, enclosures (housings) are provided in accordance with the sizes (width sizes) of the HDDs. Therefore, it is difficult to mount the two types of HDDs of the 3.5-inch type and the 2.5-inch type in a mixed manner on the mounting device.
The 2.5-inch type HDD can be mounted on a slot portion of a 3.5-inch type mounting device. In this case, however, there is a problem in that the advantage of the small size of the 2.5-inch type HDD is impaired.
Furthermore, if two 2.5-inch type HDDs are mounted in the depth direction of the slot portion formed for the 3.5-inch type HDD in the mounting device, there is a problem in that removal of the HDD mounted on the back side requires prior extraction of the HDD mounted on the front side.
The problems of such a conventional mounting device will be described below with reference to FIG. 14 and FIG. 15. FIG. 14 is a view for explaining an operation performed for a conventional mounting device. FIG. 15 is a view for explaining a modification of the mounting device.
Specifically, as illustrated in FIG. 14, in the case where 2.5-inch type HDDs 30 and 40 are housed in slot portions on the front side and the back side inside of a mounting device 10′, when the HDD 40 on the back side is to be extracted, the HDD 30 on the front side becomes an obstacle. Therefore, there is a problem in that the HDD 40 on the back side is not extracted until the HDD 30 is extracted toward the front.
If the height of the mounting device 10′ is made large to prevent the HDD 30 on the front side from becoming an obstacle when the HDD 40 on the back side is extracted, the HDD 40 on the back side can be extracted. In this case, however, there is a problem in that the height and the size of the mounting device 10′ are made large because a space through which the HDD 40 on the back side passes needs to be secured (height H<height H′).